The development and testing of experimental hypotheses which study drug action utilizing in vitro and in vivo models, and the translation of results from model systems to clinical trials, requires accurate quantitation of drug exposure in the model system. Knowledge of drug disposition in the model system, including stability of parent compound and its metabolic fate, is essential in interpreting experimental results. Accurate determination of drug exposure is required during multiple stages of drug development, ranging from studies of target identification to translation of laboratory findings into clinical trials. The Pharmacokinetics Core Laboratory is a 2200 square foot state-of-the-art facility. Analytical equipment includes Waters HPLC Alliance Systems with photo diode array, ultraviolet dual-wavelength, fluorescent, electrochemical and LC/MS detectors, giving the laboratory an ability to analyze a broad spectrum of therapeutic agents in biologic matrices. Analyses are performed in accordance with the FDA's Good Laboratory Practices standards. The laboratory has both developed novel assays and implemented previously described assays for a range of anti-cancer compounds. The objectives of the core are: 1. To provide core pharmacokinetic support for in vitro and in vivo model systems of neuroblastoma. 2. To develop and validate drug assays for standard and investigational agents utilized in in vitro and in vivo model systems of neuroblastoma.